The field of the invention is the treatment of tumors, and particularly, the identification of a region to be treated with a radiation therapy device or the like.
There are currently three common methods used to communicate key operative findings to a radiation oncologist for use in intra-operative and post-operative radiation therapy. First, the surgeon may describe the operative findings, both by speaking directly with the radiation oncologist, and by dictating his findings in the operative note. With this method, the radiation oncologist makes a best attempt to utilize this information by digitizing the area of concern described by the surgeon on a CT image that has been imported to the radiation therapy planning workstation. Much can be lost in this translation. In addition, it is often considerably more difficult to precisely identify a soft tissue area of concern on a post-operative CT scan than it is to identify it intra-operatively, especially when the person identifying the area of concern intra-operatively (the surgeon) is usually different than the person attempting to identify the same area on the post-operative CT scan (the radiation oncologist).
Second, the surgeon may embed radio-opaque metallic clips into soft tissue surrounding the area of concern, to outline the area of concern. The radiation oncologist then identifies these clips on the simulation film or planning CT images, and adjusts the radiation field shape to ensure that the clips are incorporated in the treatment field. However, interpreting the area of concern (a three-dimensional shape) on a two-dimensional simulation film can cause the radiation oncologist to misinterpret the area of concern. In addition, the clips do not outline the entire border of concern. Rather, three to six “representative” clips are generally placed, spread over the entire border of concern. Finally, it can be difficult to differentiate these clips from clips placed for other purposes at the time of surgery, and the tumor identification clips can be difficult to find on the post-operative planning CT images.
Third, intra-operative irradiation may be delivered by directly visualizing the area of concern, and adjusting the linear accelerator electron cone in an attempt to ensure that the area of concern is contained within the borders of the cone. Poor lighting, blood pooling, the placement of suction devices, the use of bolus material to increase dose at the surface, difficult angles, and visual obstruction caused by the cone can make targeting vague. Clips may be placed by the surgeon to outline the area of concern, but for the reasons described above, these clips can be difficult to visualize as the radiation oncologist sets the electron cone position.